AARS2-Mediated Lactylation of ULK1 Promotes Autophagy-Dependent Progression of Clear Cell Renal Cell Carcinoma

Autophagy is an evolutionarily conserved degradation pathway wherein cytoplasmic components are sequestered within double-membrane autophagosomes for lysosomal delivery. The initiation of autophagy is governed by autophagy-related (Atg) proteins, with the ULK1 kinase complex serving as the most upstream regulator. The recruitment of the ULK1 complex to sites of autophagosome formation is a pivotal yet poorly understood step in autophagy initiation. Here, we discover that ULK1 undergoes lactylation at lysine 46, catalyzed by the mitochondrial aminoacyl-tRNA synthetase AARS2, in response to autophagic stimuli. This modification is essential for targeting ULK1 to autophagosome formation sites and triggering autophagy. Moreover, lactylation potentiates the kinase activity of ULK1, leading to enhanced phosphorylation of its substrate ATG14. This phosphorylation event is crucial for the activation of the class III phosphatidylinositol 3-kinase complex and the subsequent generation of phosphatidylinositol 3-phosphate (PI3P), a lipid essential for autophagosome membrane formation. Furthermore, we demonstrate that the AARS2-mediated lactylation of ULK1 drives autophagic flux and promotes metastasis in clear cell renal cell carcinoma (ccRCC). Our study identifies lactylation as a novel regulatory mechanism controlling autophagy initiation and suggests that targeting the AARS2-ULK1 lactylation pathway could be a potential strategy for treating ccRCC.